Perforating implement with stripper sleeve retaining means



p 1960 B. w. GROSSMAN PERFORATING IMPLEMENT WITH STRIPPER SLEEVERETAINING MEANS Filed Sept. 20, 1956 INVENTOR BERT W GROSSMAN arramvsr jUnited States Patent @fiice Patented Sept. 20, 1960 PERFORATINGI1VIPLEMENT WITH STRIPPER SLEEVE RETAINING MEANS Bert W. Grossman, ErieCounty, N.Y., assignor to George F. Wales, Kenmore, N .Y.

Filed Sept. 20, 1956, Ser. No. 610,993

1 Claim. (Cl. 83-140) The present invention relates to perforatingapparatus and more particularly to self-contained perforatingimplements.

The conventional self-contained perforating implement comprises aC-frame in the lower arm of which is mounted a die, and in the upperarmof which is mounted a punch-stripper assembly. The punch-stripperassembly conventionally comprises a combined stripper and guide-sleevewhich is reciprocable in the upper arm of the C-frame and in which thepunch is reciprocable. A coil spring is interposed between the punch andthe sleeve, in which energy is stored during the perforation of thework, which energy is released upon relief of the punching pressure tostrip the punch from the work. Another spring is interposed between thesleeve and the upper arm of the C-frame to restore the punch-stripperassembly to original position upon completion of the punching operation;and a retainer clip is secured to the C-frame to limit the returnmovement of the stripper or guide-sleeve to prevent the sleeve frombeing thrown out of the C-frarne on this return movement. A dull punchtends to jam in the work, and will let go-suddenly under the strippingforce. Since a set screw or the like is provided to limit the upwardstripping movement of the punch in the sleeve, the accelerated strippingmovement of the punch will be transmitted to the sleeve. Unless somemeans is provided, therefore, to limit the upward movement of the sleeveit may be ejected from the holder by the suddenly-applied strippingforce as the punch lets go of the work. If the sleeve should be ejectedfrom the holder, its ejection might not be noticed by the operator, andit might wedge into such a position as to damage the press, or the work,or a perforating implement on the next down-stroke (working stroke) ofthe ram of the press. In any event, if the sleeve is ejected from theholder and not noticed, that means that a hole will not be punched inthe work on the next down-stroke of the ram. This will mean a spoiledpiece of Work, or require a repeat punching operation. A stop orretainer clip for the sleeve is, therefore, a very important part for apractical self-contained perforating implement.

Heretofore, the retaining clip has been made of a rectangular block ofhardened steel and has been secured in a correspondingly rectangularshaped slot in the upper arm of the 'C-frame to engage at its free endin a flat or groove in the stripper or guide sleeve. To provide therequired slot in the upper arm of the C-frame has meant an end-millingoperation.

The primary object of the present invention is to provide a retainerclip which will be less expensive than the retainer clips heretoforeused, and in which the recess in the upper arm of the C-frame for theretainer clip can be formed by a counter-boring operation instead ofrequiring an end-milling operation.

Another object of the invention is to provide a retainer clip which willbe stronger than previous retainer clips.

Other objects of the invention will be apparent hereinafter from thespecification and from the recital of the appended claim.

In the drawing:

Fig. 1 is a part side elevation, part section of a perforating unit madeaccording to one embodiment of this invention;

Fig. 2 is a section on the line 22 of Fig. 1 looking in the direction ofthe arrows;

Fig. 3 is a perspective View of one form of retainer clip made accordingto the present invention; and

Fig. 4 is a perspective View of a modified form of clip.

Referring now to the drawing by numerals of reference, 10 denotes theC-frame of a perforating implement provided with a retainer clip madeaccording to the present invention. The C-frame has an upper arm 11 anda lower arm 12. One type of conventional pedestal die 13 is secured tothe lower arm of the C-frame; and the lower arm has a pilot pin 14 forpositioning the perforating implement on a templet on the bed of a punchpress.

Reciprocably mounted in the upper arm 11 of the C-frame in axialalignment with the die 13 is a punchstripper assembly 15 comprising acombined stripper and guide-sleeve 16 which is reciprocable in the upperarm of the C-frame, the punch 18 which is reciprocable in the sleeve 16,and the coil stripper spring 19, which is interposed between theenlarged head 20 of the sleeve 16, and the enlarged head 21 of thepunch. This punchstripper assembly is normally held, in the upperposition shown in Fig. 1 by a coil spring 22 which is interposed betweensleeve head 20 and the upper arm 11 of the C-frame. Spring 22 acts toreturn the punch stripper assembly to its upper position aftercompletion of the perforating operation. A set-screw 24, which isthreaded into the sleeve head 29 and which engages in a flat or groove25 in the punch, serves to limit reciprocating movement of the punch inthe sleeve 16.

In a perforating operation, when the ram of the punch press descends, itstrikes the head 21 of the punch forcing the punch and the strippersleeve downwardly, compressing the lifter spring 22. When the bottomface of the sleeve 16 engages the metal sheet or other workpiece whichis to be perforated, its motion is stopped, but the downward motion ofthe punch continues, to perforate the workpiece. During the perforatingoperation the spring 19 is compressed. As the ram of the press ascends,the spring 19 expands again to strip the punch from the work.Thereafter, as the ram continues to ascend, the lifter spring 22 expandsto return the sleeve 16 and the parts carried thereby to their initialpositions.

To prevent the stripper-sleeve and the punch assembly from being ejectedor thrown out of the C-frame by the expanding lifter spring, theretainer clip 30 is provided.

According to the present invention this retainer clip is made bystamping out a clip which is cylindrical around most of its peripherybut which has a flatted slide 31. The flat part of the clip engages in aflat or groove 32 formed in one side of sleeve 16. The flat or groove 32forms shoulders on the sleeve 16 at opposite ends of the fiat or groovewhich are engaged by the clip 30, thereby to limit the upward movementof the sleeve in arm 11, to prevent the punch-stripper assembly,including the sleeve, from being ejected from the C-frame. The retainerclip also serves the purpose of preventing the punch-stripper assemblyfrom falling out of the perforating implement should the perforatingimplement be turned upside down when it is being transported.

The clip itself is seated in a recess 34 formed in the upper arm of theC-frame by counterboring the upper arm of the C-frame. The recess 34overlaps the bore in upper arm 11 in which sleeve 16 reciprocates;hence, counterboring of recess 34 is easy. The clip is held in thisrecess by a screw 35 which passes through a hole 36 in the clip andthreads into a tapped hole 37 in the upper arm of the C-frame. p

40 denotes a conventional locating pin or gauge bar which acts to limitthe distance to which the, sheet metal or other stock, that is to beperforated, can be fed between the punch and the die, thereby todetermine the distance from the inner edge of the sheet at which thehole is punchedin the sheet. This locating pin' or gauge bar is mountedin an opening in the upright portion of theO-frame and is secured'inconventional manner in any adjusted position by a set-screw 42 whichthreads into the upper arm of the C-frame and which engagesgthe locatingpin or gauge bar,

, 1 In Fig. 4 there is illustrated a somewhat rnodified forirn 30 ofretainer clip which is partially milled away on its lower surface, asdenoted at 31', to provide a lip for engagement flat or groove 32 of theguide sleeve'16. The big advantage of the retainerclip of the presentinvention over prior types of retainer clips is in the simplicity of theoperation required to make the recess 34 in the holder for the clip.With the type of retainer clip employed by the present invention,this'recess can be counterbored, whereas heretofore anend-milling'operation has been required to provide a recess in the upperarm of the O-frame for the retaining clip. 7 7

While the invention has been described in connection with diflerentembodiments thereof, it will be understood that it is capable of furthermodification, and this applica- 5 tion is intended to cover anyvariations, uses, or adaptations of the invention following, in general,the principles of the invention and including such departures from thepresent disclosure as come within known or customary practice in the artto which the invention pertains and as fall within the scope of theinvention or the limits of the appended claim.

Having thus described my invention, what I claim is:

In a perforating implement having a O-frame with an upper stationary armand 'a lower stationary arm, a stripper sleeve reciprocable in a bore insaid upper arm, a punch reciprocable in said stripper sleeve, springmeans interposed between' s aid punch and said sleeve to strip the punchfrom the work upon completion of a perforating operation, ,and secondspring means interposed between said sleeve and said-upper arm forconstantly urging the sleeve and the'punch mounted therein toinoperative position, the improvement in combination therewith of anarcuate recess whichpopens upwardly from the upper surface of said upperarm, said recess joining said bore,' said sleeve having a slabbed-offflat groove extending for a part of its axial length and terminatingintermediate its ends and confronting said recess, a retainingmember insaid recess, and a single screw for securing said retaining membertherein, said retaining member having'a flat surfaceat one edgesubstantially coplanar with said groove to permit'liin'ite'd axialmovement o'ftsaid strippersleeve in said bore, to preclude angularmovement'tof said stripper sleeve in said bore, and to prevent ejectionof said sleeve from said upper arm, said retaining member having acrosssectional configuration'in a plane perpendicular to the directionof punch reciprocation, a major part of which configuration includesanarcuate periphery fitting closely in said recess.

References Cited in the file of this patent TED STATES PATENTS

